ManipulateColor.java

/**
 * https://stackoverflow.com/questions/33072365/how-to-darken-a-given-color-int
 * @param color color provided
 * @param factor factor to make color darker
 * @return int as darker color
 */
public static int manipulateColor(int color, float factor) {
    int a = Color.alpha(color);
    int r = Math.round(Color.red(color) * factor);
    int g = Math.round(Color.green(color) * factor);
    int b = Math.round(Color.blue(color) * factor);
    return Color.argb(a,
            Math.min(r, 255),
            Math.min(g, 255),
            Math.min(b, 255));
}